Continuous, Label-Free Phenotyping of Single Cells Based on Antibody Interaction Profiling in Microfluidic Channels.

Area of Science:

• Biotechnology
• Cell Biology
• Microfluidics

Background:

• Traditional flow cytometry requires fluorescence labeling and extensive sample preparation, limiting analysis of cells under native conditions.
• Developing label-free methods is crucial for preserving cellular integrity and enabling real-time analysis.

Purpose of the Study:

• To present a novel label-free flow cytometry technique for phenotypic cell characterization.
• To demonstrate the spatiotemporal resolution of cell-surface interactions in microfluidic channels.

Main Methods:

• Utilized computational imaging to track numerous cells across a large field of view (12 × 3 mm²).
• Employed antibody-coated microfluidic channels to analyze cell motion profiles.
• Targeted T-cell receptor CD8 for proof-of-principle experiments.

Main Results:

• Successfully tracked individual T-cells in 98% of cases at flow velocities of 1-3 mm·s⁻¹.
• Differentiated CD8-positive and CD8-negative cells based on temporary motion delays caused by surface interactions.
• Achieved a clear contrast ratio of 23.9 ± 11.6 between cell types at 1 mm·s⁻¹.

Conclusions:

• The developed label-free flow cytometry method effectively characterizes cells without prior labeling or sample preparation.
• This technique offers a promising approach for analyzing cells in their native state, enhancing diagnostic and research capabilities.